Browsing by Author "Chen, MS"

Now showing 1 - 9 of 9

A novel fully CMOS process compatible PREM for SOC applications
(2005-03-01)
Yeh, CC
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Wang, TH
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Tsai, WJ
;
Lu, TC
;
Liao, YY
A novel nonvolatile memory cell named programmable resistor with eraseless memory (PREM) is proposed for system on chip applications for the first time. PREM combines a novel "eraseless" algorithm and the progressive breakdown of an ultrathin oxide. No or one extra mask is needed with a standard CMOS process. Multitime programming, multilevel cell, nonvolatility, and low-voltage operation are realized. Good reliability is demonstrated based on the result of a single cell.
A novel PHINES flash memory cell with low power program/erase, small pitch, two-bits-per-cell for data storage applications
(2005-04-01)
Yeh, CC
;
Wang, TH
;
Tsai, WJ
;
Lu, TC
;
Chen, MS
A novel programming by hot-hole injection nitride electron storage (PHINES) Flash memory technology is-developed. The memory bit size of 0.046 mu m(2) is fabricated based on 0.13-mu m technology. PHINES cell uses a nitride trapping storage cell structure. Fowler-Nordheim (FN) injection is performed to raise V-t in erase while programming is done by lowering a local V-t through hand-to-hand tunneling-induced hot hole (BTBT HH) injection. Two-bits-per-cell feasibility, low-power and high-speed program/erase, good endurance and data retentivity make it a promising candidate for Flash EEPROM technology in gigabit era applications.
An endurance evaluation method for flash EEPROM
(2004-05-01)
Zous, NK
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Chen, YJ
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Chin, CY
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Tsai, WJ
;
Lu, TC
Trap generation is hard to estimate in a Flash cell due to a dynamic stress field during program and erase. In this paper, a linear correlation is found between the erase state V-T rollup, and cycling V-T window. With the knowledge of the time dependence of erase stress field based on Fowler-Nordheim (FN) tunneling, the V-T rollup during cycling is evaluated by incorporating field dependent oxide trap generation. The extracted Delta V-T degradation slope during constant FN stress can be applied quantitatively to predict the V-T window closure during Flash cell cycling.
Design and performance studies of an adaptive cache retrieval scheme in a mobile computing environment
(2005-01-01)
Peng, WC
;
Chen, MS
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資訊工程學系
;
Department of Computer Science
In a mobile computing system, as users move to a new service area, the new server is usually considered to take over the execution of running programs for mobile users from the previous server so as to reduce the communication overhead of a mobile system. This procedure is referred to as service handoff. Note that when service handoff occurs, the new server will lose its advantage for cache access. To remedy this, we explore in this paper several cache retrieval schemes to improve the efficiency of cache retrieval. In particular, we analyze the impact of using a coordinator buffer to improve the overall performance of cache retrieval. Moreover, in light of the properties of transactions (i.e., temporal locality of data access among transactions), we devise a Dynamic and Adaptive cache Retrieval scheme (DAR) that can utilize proper cache methods according to some specific criteria to deal with the service handoff situation in a mobile computing environment. Performance of these cache retrieval schemes is analyzed and a system simulator is developed to validate our results. We devise a systematic procedure for determining the optimal operating points of DAR. Our experimental results show that by adaptively adopting the advantages of different cache retrieval methods, DAR significantly outperforms other schemes and is particularly effective for a mobile computing environment.
Fabrication and characterization of gated Si field emitter arrays with gate aperture below 0.5 mu m
(1995)
Ku, TK
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Hsieh, BB
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Chen, MS
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Wang, CC
;
Wang, PW
On exploring the power-law relationship in the itemset support distribution
(2006)
Chuang, KT
;
Huang, JL
;
Chen, MS
;
資訊工程學系
;
Department of Computer Science
We identify and explore in this paper an important phenomenon which points out that the power-law relationship appears in the distribution of itemset supports. Characterizing such a relationship will benefit many applications such as providing the direction of tuning the performance of the frequent- itemset mining. Nevertheless, due to the explosive number of itemsets, it will be prohibitively expensive to retrieve characteristics of the power-law relationship in the distribution of itemset supports. As such, we also propose in this paper a valid and cost-effective algorithm, called algorithm PPL, to extract characteristics of the distribution without the need of discovering all itemsets in advance. Experimental results demonstrate that algorithm PPL is able to efficiently extract the characteristics of the power-law relationship with high accuracy.
On the effect of group mobility to data replication in ad hoc networks
(2006-05-01)
Huang, JL
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Chen, MS
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資訊工程學系
;
Department of Computer Science
The growth in wireless communication technologies attracts a considerable amount of attention in mobile ad hoc networks. Since mobile hosts in an ad hoc network usually move freely, the topology of the network changes dynamically and disconnection occurs frequently. These characteristics make it likely for a mobile ad hoc network to be separated into several disconnected partitions, and the data accessibility is hence reduced. Several schemes are proposed to alleviate the reduction of data accessibility by replicating data items. However, little research effort was elaborated upon exploiting the group mobility where the group mobility refers to the phenomenon that several mobile nodes tend to move together. In this paper, we address the problem of replica allocation in a mobile ad hoc network by exploring group mobility. We first analyze the group mobility model and derive several theoretical results. In light of these results, we propose a replica allocation scheme to improve the data accessibility. Several experiments are conducted to evaluate the performance of the proposed scheme. The experimental results show that the proposed scheme is able to not only obtain higher data accessibility, but also produce lower network traffic than prior schemes.
Photonic band structure for a superconductor-dielectric superlattice
(2005-11-15)
Wu, CJ
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Chen, MS
;
Yang, TJ
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電子物理學系
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Department of Electrophysics
The photonic band structure in the transversal electric mode for a one-dimensional superconductor-dielectric superlattice is theoretically calculated. By using the Abeles theory for a stratified medium, we first calculate the transmittance spectrum from which all the possible bands can be directly seen. Then we calculate the real photonic band structure based oil the transcendental equation derived from the transfer matrix method and Bloch theorem. The band structure is shown to be strongly consistent with the transmittance spectrum. We finally study the three lowest band gaps as a function of penetration of superconductor, permittivity of dielectric, and angle of incidence, respectively. The optical properties in a superconductor-dielectric superlattice thus are well disclosed. (c) 2005 Elsevier B.V. All rights reserved.
Query processing in a mobile computing environment: Exploiting the features of asymmetry
(2005-07-01)
Peng, WC
;
Chen, MS
;
資訊工程學系
;
Department of Computer Science
With the cutting edge technology advance in wireless and mobile computers, the query processing in a mobile environment involves join processing among different sites which include static servers and mobile computers. Because of the need for energy saving and also the presence of asymmetric features in a mobile computing environment, the conventional query processing for a distributed database cannot be directly applied to a mobile computing system. In this paper, we first explore three asymmetric features of a mobile environment. Then, in light of these features, we devise query processing methods for both join and query processing. Intuitively, employing semijoin operations in a mobile computing environment is able to further reduce both the amount of data transmission and energy consumption. A semijoin which is initiated by a mobile computer ( respectively, the server) and is beneficial to reduce the cost of a join operation is termed a mobile- initiated or MI ( respectively, server- initiated or SI) profitable semijoin. According to those asymmetric features of a mobile computing system, we examine three different join methods and devise some specific criteria to identify MI/ SI profitable semijoins. For query processing, which refers to the processing of multijoin queries, we develop three query processing schemes. In particular, we formulate the query processing in a mobile computing system as a two- phase query processing procedure that can determine a join sequence and interleave that join sequence with SI profitable semijoins to reduce both the amount of data transmission and energy consumption. Performance of these join and query methods is comparatively analyzed and sensitivity analysis on several parameters is conducted. Furthermore, we develop a systematic procedure to derive the characteristic functions of MI and SI profitable semijoins. It is noted that, given some system parameters, those characteristic functions are very important in determining which join method is the most appropriate one to employ in that configuration. It is shown by our simulation results that, by exploiting the three asymmetric features, these characteristic functions are very powerful in reducing both the amounts of energy consumption and data transmission incurred and can lead to the design of an efficient and effective query processing procedure for a mobile computing environment.